Experimental cross-polarization detection of coupling far-field light to highly confined plasmonic gap modes via nanoantennas

TL;DR

This paper demonstrates an experimental method to detect weakly coupled plasmonic gap modes using nanoantennas and polarization control, significantly improving signal detection in nanophotonics.

Contribution

It introduces a novel experimental approach for cross-polarization detection of plasmonic gap modes via nanoantennas, enhancing measurement sensitivity.

Findings

Coupling of far-field light to plasmonic gap modes depends on polarization, position, and wavelength.

Crossed polarization measurements detect weak signals from gap waveguides.

Signal-to-noise ratio is dramatically increased using the proposed method.

Abstract

We experimentally demonstrate the coupling of far-field light to highly confined plasmonic gap modes via connected nanoantennas. The excitation of plasmonic gap modes is shown to depend on the polarization, position and wavelength of the incident beam. Far-field measurements performed in crossed polarization allow for the detection of extremely weak signals re-emitted from gap waveguides and can increase the signal-to-noise ratio dramatically.